The generator is a machine which converts mechanical energy obtained from sources of various types of energy such as physical, chemical or nuclear power energy, for example, into electric energy. Generators based on linear motion have recently been developed while most generators are structured as rotational type generators. Generation of electromotive force by electromagnetic induction is a common principle to generators regardless of their size or whether the generator is AC or DC generator.
The generator requires a strong magnet such as permanent magnet and electromagnet for generating magnetic field as well as a conductor for generating the electromotive force, and the generator is structured to enable one of them to rotate relative to the other. Depending on which of the magnet and the conductor rotates, generators can be classified into rotating-field type generators in which the magnetic field rotates and rotating-armature type generators in which the conductor rotates.
Although the permanent magnet can be used for generating the magnetic field, the electromagnet is generally employed which is formed of a magnetic field coil wound around a core to allow direct current to flow therethrough. Even if a strong magnet is used to enhance the rotational speed, usually the electromotive force produced from one conductor is not so great. Thus, in a generally employed system, a large number of conductors are provided in the generator and the electromotive forces generated from respective conductare serially added up so as to achieve a high electric power.
As discussed above, a usual generator produces electricity by mechanically rotating a magnet (or permanent magnet) or a conductor (electromagnet, electrically responsive coil and the like) while reverse current generated at this time by magnetic induction (electromagnetic induction) and flowing through the coil causes magnetic force which pulls the rotor so that the rotor itself is subjected to unnecessary load which reaches at least twice the electric power production.
FIG. 6 illustrates that the load as discussed above is exerted on a rotor in a rotating-field type generator mentioned above.
Referring to FIG. 6, a permanent magnet train 104 is arranged about an axis of rotation 106 such that N poles and S poles are alternately located on the outer peripheral surface of the train. At a certain distance outward from the outer periphery of permanent magnet train 104, a magnetic induction core 100 is arranged and a coil 102 is wound around magnetic induction core 100.
As permanent magnet train 104 rotates, the magnetic field produced in the coil by permanent magnet train 104 changes to cause induced current to flow through coil 102. This induced current allows coil 102 to generate a magnetic field 110 which causes a repulsive force exerted on permanent magnet train 104 in the direction which interferes the rotation of the magnet train.
For example, in the example shown in FIG. 6, the S pole of magnetic field 110 faces permanent magnet train 104. The S pole of permanent magnet train 104 approaches coil 102 because of rotation of permanent magnet train 104, resulting in the repulsive force as described above.
If reverse current flows in a responsive coil of an armature wound around a magnetic induction core of a generator so that the resulting load hinders the rotor fiom rotating, reverse magnetic field of the armature responsive coil becomes stronger in proportion to the electricity output and accordingly a load corresponding to at least twice the instantaneous consumption could occur.
If electric power of 100W is used, for example, reverse magnetic field of at least 200W is generated so that an enormous amount of load affects the rotor to interfere the rotation of the rotor.
All of the conventional generators are subjected to not only a mechanical primaly load, i.e. the load when the electric power is not consumed but a secondary load due to reverse current which is proportional to electric power consumption and consequently subjected to a load of at least twice the instantaneous consumption.
Such an amount of the load is a main factor of reduction of the electric power production efficiency, and solution of the problem above has been needed.